Method of and apparatus for coating sheet metal container side seams



Nov. 2s, 1939. s, LFLUGGE 2,181,319

METHOD OF AND APPARATUS FOR COATING SHEET METAL CONTAINER SlDE SEAMS Filed Dec. 15, 1937 2 Sheets-Sheet l ,lf/Mfr@ .maj

NOV. 28, 1939. l SML FLUGGE 2,181,319 4 METHOD OF AND APPARATUS FOR COATING SHEET METAL CONTAINE SIDE SEAMS Filed Dec. `15, 193'?y 2 vsneetssneet 2 Patented Nov. 28, 1939 UNITED STATES F AND APPARATUS FOR COATING SHEET METAL CONTAINER SIDE SEAMS Sylvester L. Flugge, Chicago, Ill., assignor to Continental Can-Company, Inc., New York, N. Y.,

a corporation of New York Application December 1937, Serial No. 180,052

9 Claims. (Cl. 113-7) 'I'he invention relates generally to the art of interiorly coating containers while they are in process of formation and'primarily seeks to provide a novel method of and apparatus for ap- 5 plying a stripe of suitable protective coating material along the'side seams interiorly of the containers as they are being fed along in the forming machine. Many products, such as beer, wine, carbonated l0 water, grape juice. and cranberry juice, cannot l be packed in metal cans unless a protective lining is used that completely insulates the product from the metal of the can.` Thede ign of cans is generally such that the side sea s are the 16 most diilicult portions of the vcans to cover with protective coatingssuch as lacquer or' enamel illms. Thus, inthe coating of can bodies by the well known methods of dipping, flushing, or spraying, several coating applications have been 20 necessary in order to provide adequate protection at the side seams, resulting in greatA waste of coating materials as a result of the extra coatings not needed at the main body portions of the cans. Attempts to coat th can body blanks prior to the shaping thereof have been but partially successful since the seam portions necessarily are scraped and marred during the formation of the side seams. 'These4 diculties have brought about the practice of precoating the Vbody blanks except at the edges to be interlocked in the formation ofthe side seams and subsequently applying a protective stripe over the formed side seams, although .the side seams may be coated prior to the application of overall inv terior coatings, if desired, so as to provide a double coating only at the seams.

Prior to the present invention, the side seam stripping was applied justafter the can body sideseams had been solder-bonded.v In order to assure perfect alignment the striping must be applied while the can bodies are oriented, or travelling along under position control, on the body maker. Just after leaving the solder-bonding station, however,x`the side seams are quite hot and diliculty has been experienced in applying the striping over these hot surfaces.

In the present invention the side seam striping is applied after the side seams are formed and before the seams are solder-bonded, the heat at the solder-bonding station being' utilized to heatharden or bake the stripe coating. When the stripe coating is applied by means positioned in advance of the solder-bonding station, say for example` on the stub horn, theV heat of the so1der` ing operation will drive 9H lvents and ehem;-

cally convert asuitable striping material to an insoluble protective lm. Since the material is applied to the seams before soldering, and at room temperature, the diiiiculties brought about by high and variable. temperatures of the seam`v- 5 are eliminated from the step of actually applying the striping. Furthermore, the positioning ci the side seams is denite and constant and no orienting difficulties are presented. A solvent.-

having a high boiling point and which will give 10` a good iilm deposition may be used since it will I l be driven oil during the bake provided in the solder-bonding operation. This bake also is'used to chemically convert .the striping lm. The' heat at 'the solder-bonding station is thus used 16 to evaporate solvents without resort to special ovens and also provides a high bake for special heat convertable films which could not otherwise be used, because a high bake after soldering would be detrimental to the soldered seams. 20

Inlits more detailed nature, therefore, the invention resides in the provision of a novel method of Vand apparatus for' shaping" can bodies and forming side seams longitudinally therein, vmoving the canbodies longitudinally whilegmain- 25 taining the seams in a common line, applying a stripe of protective coating material along the seams, and simultaneously solder-bonding the seams and heat-hardening' said striping.

With these and other objects in view that will 30 more `fully appear, the nature of the invention will be more clearly understood by following the description, the appended claims, and the several views illustrated in the accompanying drawings.

Inthe drawings, L 36 Figure 1 is'a somewhat diagrammatic vertical longitudinal section illustrating the invention embodied in a can body forming apparatus.

Figure 2 is a left' end viewvof the apparatus shown in Figure 1, parts being shown in vertical -40 cross section. ,l A

Figure 3 is a vertical cross section taken on the line 3-3 011 Figure 1. f y

- Figure 4 is an enlarged fragmentary vertical longitudinal section of the horn at the stripe ap- 45- plying station.l

Figure 5 is detail vertical cross section taken at v.

the solder-bondingand stripe baking station.v

Figures 6 and '7 are detail perspective views revspectively illustrating can s eam portions before 50` and after'stripe coating thereof. n

' Can body forming machines are well known and` usually include a forming horn, means for feeding body blanks or sheets laterally orlongitudi- Bally vto the horn, means for shaping the blanks u lV ing means 6; and the oscillating arm 1 by which about the hom and for longitudinally seaming the bodies and bumping the seams, means for feeding the formed bodies along the horn, and

means for-solder-bonding the longitudinal body seams. All such devices are shown in detail in prior patents of which Troyer, 1,772,820, of August 12, 1930, is an example, and they, of themselves,

. form no part of the present invention except insofar as they form supporting elements in novel combinations hereinafter to be described.

In the practical development'of the invention the body blanks may be fed to the forming devices in the manner shown in the Troyer patent.

or in `any approved manner. The body shaping dYiQES herein generally designated 5, the bumpmovement is transmitted to the formed body feeding means, may be constructed and operated generally as shown in the Troyer patent, and a seam bonding or soldering means 8 of the roll or any other approved type may be employed. Likewise, any suitable heating means generally designated 9 may be employed to produce the heat.

essential at the composite solder-bonding and stripe baking station.

Suitable reciprocating feed bars I0, to which motion is imparted by the arm 1, move the formed can bodies Il step-by-step along the cylindrical horn I2. The horn I2 is grooved as at I3 to receive and guide the side seams until feed and guide control is taken over by the chain I4 which y continues the feeding of the can bodies along and oi the horn I2, intoand through the outside horn. The outside h'orn comprises a pair of spaced members I5 having opposed half-cylindrical sup'- porting surfaces I6 for receiving the travelling can bodies. In advance or ahead of the solder-bonding station, the horn I2 has its under surface recessed as at l1 to receive a hollow casing I8 including a removable end wall I9 and adapted to'be removably 'secured inthe recess as indicated at 20.

The casing' is o'pen along the bottom as at 2| to.

permit an applicator roll 22 to project therefrom :in position for contacting can body seams along the full length thereof as shown in Figures 1 and 3 of the drawings. The roll 22 has trunnion bearings, as at 23, in the respective end walls of the casing.

The applicator roll 22 may take the form'of a.

- brush, or it may be provided with a soft absorbent a pipe line 25, removably secured as at 26 to the.

sheath, and a perforated drip pipe 24 is mounted in the casing above the roll for the purpose of supplying coating material to said roll' to be in turn deposited by the roll along the can body side seams.` The coating material is supplied by casing and extended through a bore provided therefor in the horn I2, from a suitable drip cup or reservoir 21. Rotation is imparted t the vroll by a. drive shaft 28 removably connected to one end of the roll, as at 29, and projected through Y the horn for connection'with any suitable driv-- can body is striped with the coating material by f the rotating roll 22. 'Ihe conveyor I4 then feeds the striped can bodyv oi the horn I2 and into the 'outside horn I5, I6 to the solder-bonding and baking station. During the-feeding k0i i211@ can ture is but a few seconds.

bodies the. horn groove l3vand the hook lugs on the feeding devices I0 and I4 maintain position control over the can bodies, assuring proper alignment of the side seams with the coating and soldering rolls. At the last mentioned station the side seam is solder-bonded and the protective coating material is suitably baked or heat-hardened, and after the conclusion of this'step of thel method the can bodies may be fed oil' into the receiving lines by a suitable feed oi conveyor 3|.

The can bodies may be thus seam striped before or after protective coatings are applied to the remaining surfaces of said bodies. In Figures 6 -and 7 I have illustrated portions of a can body in which the blank had been coated, except for the edge portions in lwhich the side seam was to be formed, prior to being fed into the body forming apparatus. The s eam of the can body is indicated at 32, and the solder-bonding at 33.

` Body coating material is indicated' at 34, being terminated at 35, just short of the seam, leaving bare spaces 36. lBare spaces thus left, as well as the seam structure 32, are adequately coated by the protective stripe 31 applied as hereinbefore described.

It isV to be understood that the specic apparatus elements herein disclosed are merely exemplary in nature and may be variously altered without departing from the spirit of either the method or the apparatus phase of the invention.

For example the applicator device may comprise a `stationary drag, or may take the form of a brush or roll rotatable about a transverse instead of longitudinal axis. It is possible also to perform the seam bonding and stripe baking step at a welding instead of a soldering station.

Two types of film forming striping material may be used: (l) a lacquer type which produces the finished film by evaporation of solvent alone with out resort to oxidization or polymerization, and (2) a heat reactive -type which produces the nished film by evaporation of the solvents plus a chemical reaction of the lm either by oxidizaton, polymerization, condensation or by combination reactions. One advantage of the reactive type is that it becomes insoluble in solvents to which it may be subjected during the application of further protective coatings -of lacquer to the inside of the can body by spraying, dipping, flooding, or flushing methods.

The temperature of the sideseam of a can body during soldering is high (450 to 600 F. or higher) but the time interval at this tempera- The striping material must have the proper `solvents in a minimum quantity so that they can be driven from the lm without causing bubbles, craters, and other undesirable lm defects. Moreover, the lm must withstand the high temperature Without blister-y ing or charring. Because the bake is short, heat ,reactive-materialsmust be designed to convert to an insoluble hard film in the very short interval available. Qrdinary polymerizing or oxidizing nishes do not react or dry fast enough to lbe used for this striping. Ordinary -driers, such as lead, manganese, cobalt and iron driers used in paints, varnishes' and enamels, will not increase sufficiently the rate of conversion to make it possible for the reaction to be complete before the seam cools..` However, the conversion of a reactive type finish may be greatly accelerated by the decomposition -of nitrocellulose which occurs when it is heated at temperatures such as are experienced during soldering.. by the properl selection and proportlonin'g of 4oil and resin, in'

combination or alone, nitrocellulose and suitable solvents, many protective nlm forming combinations can be made which4 will bake satisfactorily during the short soldering operation. The-nitrocellulose decomposition products so accelerate the Aconversion of the lm to an insoluble protective lm that the desired reaction is completed in the short time available.

Since the striping material is applied and baked on the body maker and the application and baking is completed within a few seconds in a relatively small enclosed space, there is little or no danger of damaging either the striped nlm or the machine.

I claim: y

'1. In can body forming' apparatus wherein lis provided a horn, side seam Vforming means, seam soldering means, and means including the horn and feeding devices for guiding and feeding' the cans to the soldering means with the seams properly aligned; the combination with the guiding and feeding means and the ysoldering means, of means mounted directly in the horn in advance of the soldering means for applying to the seams interiorly of the can bodies a coating of protective material thereby utilizing the heat of the .soldering operation to set the applied coating' material.

2. In can body forming apparatus wherein is provided can body forming mechanism including side seam forming means, and side seam soldering means; the combination with the soldering means of means disposed between the seam forming means and the seam soldering means for applying to the seams interiorly of the can bodiesy a coating of protective material thereby utilizing the heat of the soldering operation to set the applied coating material.

3. In can body forming apparatus wherein is provided can body forming mechanism including side seam forming means, and side seam soldering means; the combination with the soldering vmeans of means disposed between the seam forming meansand the seam soldering means for applying to the seams interiorly of the can bodies ar coating of protective material, and a horn along which the cans are guided to the soldering means, said coating material applying means being mounted directly in the horn.

4. In can bodyforming apparatus, side seam soldering means, means including a horn for guiding can bodies to the soldering means, means including an applicator roller mounted directly lin thejhorn for applying to the seams ,interiorly of the' can lbodies a coating of protective material.

A means tog-feed coating material to said roller, and

means .t6Y impart rotation' to said roller.

5. In cam body forming apparatus,.side seam soldering means, means including a horn for guiding can'bodies to the soldering means, means including an applicator roller mounted directly in the horn for applying to the seams interiorly of the canbodies a coating of protective material, means to feed coating material to said roller.

means to impart rotation to said roller, and means for feeding formed can bodies and for controlling the position of side seams thereof while passing through the coating material applying and the soldering means.

. `6. In side seamed can body forming apparatus,-

means for applying to the seams interiorly of the can bodies a coating of protective material, means for solder-bonding the seams and simultaneously heat-hardening the applied coating material, and means for feeding can bodies past the coating applying means and the solder-i bonding means with the side seams of said cans presented for engagement by each said means.

7. The method of forming can bodies and coating the seams vthereof interiorly of Athe bodies which comprises, shaping the can bodies from blanks to which a protective coating has been applied over allsurface areas to be presented inwardly of thecan bodies except such areas as are to be formed into side seams and forming side seams longitudinally therein, applying a protective coating having the qualityof becoming set by application of heat along the uncoated seam portions interiorly of the bodies, and bonding the seams by an operation in which the application of heat is inherent and utilizing said heat for heat-hardening said coating.

8. The method of forming can bodies and coating the seams thereof interiorly of the bodies which comprises, shaping the can bodies from blanksto which a protective coating has been applied over all surfaceareas to be presented inwardly of the can bodies except such areas as are to be formed into side seams and forming side seams longitudinally therein, moving the can i bodies longitudinally while maintaining .the

seams in a common line, applying a protective coating having the quality of becoming set by application of -heat along the uncoated seam porl.

tions interiorly of the bodies as they are moved along, and solder-bonding the seams and utilizing the heat incident to the solder bonding for heat-hardening said coating as the can bodies are moved along.

9'. The. method of forming can bodies and coating the seams thereof interiorly of the bodies which comprises, shaping the can bodies from blanks to which a. protective coating has been applied over all surface areas to be presented .inwardly ofthe can bodies except such areas as are to be formed into ,side seams and forming side seams longitudinally therein on the forming ing a protecti've coating hailing the quality vof becoming set by application of heat along theiuncoated seam portions interiorly'of the can bodies while they are on the relatively cool horn, moving the can bodies longitudinally while maintain-- ing the seams in a common line, and solderbonding the seams and utilizing the heat incident to the soldering function to bake the applied protective coating.

SYLVESTER L. FLUGGE. 

